| 摘要 |
A sintered polycrystalline compact of cubic boron nitride is made by first forming a mixture of about 30 to 60 percent by weight cubic boron nitride, up to about 50 percent by weight hexagonal boron nitride, and from about 2 to 7 percent by weight adjuvant materials, or sintering aids, comprising an aluminum containing material selected from the group consisting of aluminum, aluminum nitride, or aluminum diboride, and up to 50 percent by weight of nitride, carbide, or carbonitride binder material containing a group IVb, Vb, or VIb transition metal. The mixture of cBN crystals, hBN and other materials is compacted into a preform and subjected to heat treatment in a non-oxidizing atmosphere. The preform is placed onto a cemented tungsten-carbide/cobalt substrate and subjected to elevated pressure and temperature conditions at which cubic boron nitride is thermodynamically stable. The elevated pressure and temperature conditions are maintained for a time sufficient to permit the infiltration of the cobalt into the cBN matrix and sinter the compact. The compact is characterized by substantial intergranular cBN to cBN bonding, and has superior abrasive wear stability, chemical resistance, impact resistance and thermal conductivity. |
